Internal grinding machine



March 8,1960 s. L. CARLISLE 2,927,407

INTERNAL GRINDING MACHINE Filed April 8, 1958 2 Sheets-Sheet 2" INVENTORBY i wgfizzefl ATTORNFY INTERNAL GRINDING MACHINE Stanley L. Carlisle,Springfield, Vt., assignor to Bryant Chucking Grinder Company,Springfield, Vt.

Application April 8, 1958, Serial No. 727,157

7 Claims. (Cl. 51-403) This invention relates to internal. grindingmachines of the centerless type wherein a workpiece with an outerpreformed surface of revolution is radially supported to guide theworkpiece while it is being rotated. and a. tool. is applied to refineinterior surfaces of revolution in the workpiece. More particularly, theinvention re-. lates to a method and apparatus for generating at 'leasttwo different diameter surface portions. in the same. plane. which aresubstantially concentric with the preformed outer supported surface.

Accordingly, this invention provides means. for trans.- versely andcyclically shifting the relative position between the axis of. the tooland the rotative axis of the. workpiece during each revolution of theworkpiece.

This feature and related objectives will become, ap-

parent. from the following description of a preferred.

embodiment of the invention with reference to. accompanying drawings inwhich:

Fig; 1 is a front elevation view,, partially in section of the apparatusof the invention;

Fig. 2 is a top plan view, partially in section, of the apparatus shownin Fig. 1;

Fig. 3 is a fragmental detail view of the cam followerarm taken fromFig. 2;

Fig. 4 is a front elevational view, similar to- Fig. 1 but with theoperative elements inv a different position;

Fig. 5 is a view of a workpiece after a first surface refiningoperation; and

Fig. 6 is the workpiece of Fig. 5 after a second: and final surfacerefining operation.

Referring to the drawings, Figs. 1 and 2 show 'a headstock. 19 supportedon a machine bed 11. A shaft 12- is rotatably supported on bearings 15inthe headstock and is adapted to be driven through pulley 1'4 from asuitable source (not shown).

in engagement with a threaded portionof a lug 20 depending fromtheheadstock for achievinga' feed movement of the headstock, assemblytransverse to the- A rotatable tool spindle 22 supports} the axis ofshaft 12. This face is for axiallysupporv.

inga workpiece and rotatably drivingrthe. same in frictionalrelationship thereto. Fixedly attached to portion 24 and protrudingoutside face 26 is a pin 28 adaptedto engage an elongated slot 39 in theworkpiece W." By engagement between the pin 28 and a side of the slot 39the workpiece W is compelled torotatesynchronous+ In the bed 11 isj'ourna-led an axially fixed shaft 16-having a threaded portion 18 A.line running through nit Sttes Patent face' portion 37 of shoe 36 islocated to straddle the line. of feed where a wall of a workpiece may beintetposed between this shoe and the tool. The pivotal'f axis 39 of arm38 is preferably located atthe intersection. of the planes through-faceportions 35 and-37 when these planes are normal to each other. i j

"The apron 32 is provided with a. projecting lug 40 in which is threadedan adjustable stop screw 42- the end to engage a threaded portion 55 onthe extreme end of of which forms a limit stop 43 for the movement ofthe arm 38 in one direction "when an anvil 44 contacts stop 43. Alongitudinally movable thimble 46 nested in a cavity in arm 38 is heldagainst a lug 48 depending from the apron 32 by a spring 47 actingbetween the thimble and arm 38 to continuously bias the arm 38 away fromlug 4 8.

- Also depending from the apron is another lug 50, one end of which isthreaded to engage an intermediate threaded portion 53 of a shaft 52.The opposite end" of the lug 50 has a splined bore in engagement with anexternally splined nut 54, thereby preventing rotation of the nut whilstpermitting longitudinal displacement thereof. The'nut 54 has a blindhole which isthreaded the shaft 52. These threaded portions 53' and 55have different screw thread leads to form a differential screw devicefor useas an extremely fine adjustment, as is Well' known in the art.The closed end of nut 54 forms an abutment 56 to contact arm 38,.and theshaft 52 is provided with a hand wheel 58 having graduations on itsperiphery functioning as position indicating means in cooperation with afixed pointer 59.

Parallel to shaft 12 is a shaft 60 journaled'in the head stock and apronand having one end fixedly attached to a rocker arm '62 rockable in aplane parallel to the pivotal movement of arm 38. In a cavity of therocker arm 62 is nested a thimble 64 with its closed end biased againstarm 38 We spring-65 actingbetween 'the thim bleandthe rocker arm.Centrally dependent from the interior of the thimble is a stem 66passing through a hole in the bottomof the cavity. This stem is,threaded;

on the extreme portion to accommodate nuts 67" that fornran adjustablelimit stop for the thimble in the' di rection of the-force of spring 65.i

'The shaft 60- has' an extended portion 61 supporting afollower arm 70with ahub 72 keyed to the shaft ex? tension, but movable. between twolongitudinal posi tions fixed by a screw 73- in the hub and defined byin: dentations 74-74 on'theshaft. On' theouter-extreme' of the arm 70'is supported a cam follower roll 7'5: A

lobed cam 76 is fixed to the'shaft 12 through the inter f mediary of thepulley 14 and; is-rotatable therewith; The operation of the device willnow be explained;

As as example a two diameter ringgagehas been'chose n for-purposes ofillustration, and referenc'emay be" had;

toFigs'. 5- and 6. Fig. 6" illustrates such a ring gagein its finalform,-having two diametrically opposite-portions defining a majordiameter A andtwo other oppo site portions defining a minor diameter C.

lizingthe present invention isbw afirst and' secon'd op It will' ibenoted that the difference between A and} C" is for the sake of' claritygrossly exaggerated. In reality thesprea d;

eration where two portions with diameter A and two portions withdiameter B have been generated by displacing the support determinedaxis, of the workpiece relative the tool spindle axis four times duringone revolution of the gage ring. During this phase only the ma ordiameter A is sized to its final required dimension, whilst diameter Bis an arbitrary dimension re sulting from an aforesaid displacementwhich is predetermined. Diameter B is chosen so that it will be lessthan a desired minor diameter as indicated by dotted lines. After thedimension A is achieved, the cyclic displacement movement of the supportdetermined axis is stopped and the gage ring is compelled to rotateabout a fixed axis while the minor diameter C is sized utilizing theconventional operation of the grinder.

To form the two diameter ring gage the device operates as describedbelow. In Fig. 1 it is seen that cam 76 has two diametrically oppositeperipheral portions 80 joined by .intermecliate portions 81 to two otheropposite peripheral portions 82 of lesser diameter. The diametricaldifference between said portions 80 and 82 is chosen to be commensuratewith the desired maximum dilference between A and B of Fig. 5.

An annular workpiece having a pro-formed outer periphery and a pre-boredhole of lesser diameter than dimension B is placed against the face 26of the rotating driver shaft 12 with pin 28 engaging the slot 30.Because of the resultant force of the chosen eccentric relationshipbetween the driver axis and the rotative axis of the preformed surfaceon workpiece, typical of this class of grinding machines, the workpieceis compelled to be seated and radially supported by shoes 34 and 36respectively. The follower arm 76 is placed in the full line positionshown in Fig. 2 with roller 75 in contact with the periphery of cam 76,see Fig. 1, after the abutment 56 s has been backed away by turning thehand wheel 58 of shaft 52 thereby permitting follower 7 whilst incontact with cam portion 80, to actuate rocker arm 62 with the resultthat thimble 64 will abut and lift arm 38 thereby moving shoe 36 towardsthe rotative center of shaft 12 and compelling the workpiece W to slidealong face 35 parallel to the line of feed. The roller 75 of thefollower arm 70 is held against the cam by the biasing forceof spring 47and will alternately ride against portions 80 and 82 to oscillate arm 38during each revolution of shaft 12 and workpiece W, thereby moving shoe36 toward and away from the center of the system, the inward movementbeing limited by the position of abutment 56, while the combination ofthe thirnble 64 and spring 65 permits a desired amount of lost motion ofthe rocker arm 62. It will be evident that the axis 'of the workpiece Was determined by support shoes 35 and 36 will be reciprocated twiceduring each revolution thereof to thus cyclically vary the suportdetermined axis. The tool T may be brought in contact with the pre-boredhole of the workpiece by actuating the feed screw 16 in the properdirection commencing the grinding operation, and the shape of Fig. 5 isformed. Dimension B will be a function of the difference between thediameters 80 and 82 of the cam 76 and is, in this operative phase, ofsecondary importance where this dimension is chosen solely to leavestock allowance for dimension C. The spread between dimensions A and Bmay be varied within the range of the cam induced movement by adjustingthe abutment 56 and permitting more or less overtravel of the rockerarmas afforded by spring 65. After the dimension A is established thennn 70 is axially moved to the position shown in dash-dot lines in Fig.2 thereby moving follower 75 .away from cam 76. Spring 47 will thencompel arm 38 to take the position of Fig. 4 with oration. Fig. 5 showsthe gage ring after the first opthe anvil 44 seatedagainst the stop 43to place the shoe 36 in a fixed position thereby locating the supportdetermined axis of the workpiece to one singleposition along the line'of feed. The dimension C is new ground in' conventional manner tofinish the workpiece as shown in Fig. 6.

An alternative method of utilizing the device is to generate bothdimensions in one continuous operation. In this case the desired spreadbetween these dimensions is governed entirely by properly adjusting theabutment 56. From the above description it will be clear that thisspread may be established to be any desired amount less than the radial'difference between the lobes and 82 of cam'76.

The above described embodiment is susceptible to sundry variationswithout departing from the spirit and scope of the invention. Instead ofsupporting the workpiece directly on its preformed outer periphery, theworkpiece may be secured in a shuttle with a circular perimeter as is inprinciple described in copending applications Serial No. 621,862, filedNovember 13, 1956 by Lovely now Patent No. 2,836,936 granted June 3,1958, and Serial No. 729,126, filed April 17, 1958, by Terp. The drivingand rotative synchronizing means of Serial No. 621,862 (now Patent No.2,836,936) may be substituted for the above described magnetic andpin-slot driving means. Therefore applicants invention is entitled to areasonable range of equivalents as defined by the appended claims.

I claim:

1. In combination, an internal centerless grinding machine including arotatable tool spindle, a grinding tool adapted to be placed in workingrelationship with the internal siu'face of an annular workpiece, aheadstock containing a rotatable work driver provided with an end faceportion normal to the spindle axis for axially supporting an end face ofa workpiece and rotatably driving the workpiece, the tool spindle andwork driver spindle being arranged for relative transverse movementalong a.line of feed running between the axes of the tool and workdriver spindles, and improved means for radially supportingthe perimeterof the workpiece for rotation about a support-determined axis, saidimproved work support means comprising: a first support shoe rigidlyattached to the headstock for supporting the workpiece with its supportdetermined axis located substantially on the line of feed, a secondsupport shoe movably mounted on the headstock. for movement about apivot substantially along the line of feed for supporting the outsideperimeter of the workpiece in the proximity of the line of feed, andmeans for rocking said feed line support shoe about its pivot insynchronism with the rotation of the work driver spindle to cyclicallyvary the position of the support-determined axis of the workpiecesubstantially along the line of feed, during each rotation thereof,where by at least two different diameters will be generated in theinternal surface of an annular workpiece.

2. A device as defined in claim lwherein said movable shoe is rigidlymounted on a pivotable member and said means for cyclically moving saidsecond support shoe comprises a cam, a cam follower, and a rocker armoperable by the .cam follower formoving said pivotal member.

a 3." A device as defined in claim 2 wherein said cam is rigidly securedto and rotatable with the work driver spindle and said cam follower issecured to a rockable and axially movable shaft mounted on said baseparallel to said driver spindle and having the movable shoe rocker annrigidly secured thereto.

4.- A device as defined in claim 3. wherein an adjustable limit stop ismounted on the headstock for limiting the movement of the pivotablemember in one direction; and spring means acting between the rocker armand the said member permitting a lost motion of travel of the rocker armwhilst the pivotable member abuts said stop.

5. A device as defined in claim 4 wherein said stop may be selectivelypositioned in a manner'to limit the movement of the pivotable member toany desired exten- 5 sion less than the maximum amount governed by theconfiguration of the cam.

6. A device as defined in claim 4 including a second adjustable stopmounted on the headstock for limiting the movement of the pivotablemember in opposite direction; and spring means acting between theheadstock and the member in a direction towards the second stop; meansto disengage the follower from the cam, permitting said last recitedspring means to seat the pivotable member against the second stopthereby placing the feed line support shoe in a predetermined positionestablishing a fixed single position of the support determined axis ofthe workpiece on the line of feed.

7. In combination, an internal grinding machine, including a headstocksupporting a rotatable work driver for positively driving an annularworkpiece, a tool adapted to be placed in working relationship with theinterior of an annular workpiece upon which an internal surface is to begenerated having at least two difierent diameters concentric with apreformed external surface of said workpiece, means to impart a relativetransverse movement between the axes of said tool and said work driveralong a line of feed running to the axis of said tool; and an improvedwork supporting apparatus, the work supporting apparatus comprising: aradial supporting shoe fixed to said headstock for supporting saidworkpiece on a line parallel with the line of feed; a movable feed linesupporting shoe positioned to support said workpiece on its preformedouter perimeter substantially in the vicinity of the line of feed wherea wall of the workpiece may be interposed between the tool and the shoe;means for pivotally supporting said movable feed line shoe from theheadstock and cam means for cyclically rocking said movable shoe aboutits pivot to cyclically displace the supportdetermined axis of theworkpiece along said line of feed during each revolution of the workdriver and the workpiece.

References Cited in the file of this patent UNITED STATES PATENTS2,694,883 Balsiger Nov. 23, 1954 2,795,088 Schonhoft June 11, 19572,799,977 Jones- July 23, 1957 2,838,885 Cann June 17, 1958 2,838,886Lovely June 17, 1958

